‘Penis fish’ — thousands of them — stranded at Point Reyes beach

A view of Drakes beach can be seen as the fog rolls in, in Inverness, California, on Tuesday, September 27, 2016.

Photo: Gabrielle Lurie / The Chronicle

Thousands of fat, phallic-shaped innkeeper worms — often referred to as “penis fish” — have washed up on Drakes Beach after a recent storm.

The 10-inch pulsing worm, whose scientific name Urechis caupo is often overshadowed by the more colorful nickname, are among a family that only has four species in the world, one of which is found from Southern Oregon to Baja, according to Bay Nature. Most sightings of the penis fish are reported between between Bodega Bay and Monterey.

“Whether or not you feel privileged by its presence, U. caupo is an almost uniquely California experience, perhaps having the best claim for State Worm,” Ivan Parr, a Bay Nature reporter, wrote after the discovery at Point Reyes State Marine Reserve.

Their unique shape is apt for a life spent in U-shaped burrows underground, but homes made of sand are vulnerable to storms, like a recent one that left thousands of the fat worms on Drakes Beach.

“We’re seeing the risk of building your home out of sand,” Parr wrote. “Strong storms - especially during El Niño years - are perfectly capable of laying siege to the intertidal zone, breaking apart the sediments, and leaving their contents stranded on shore.”

On the internet, the penis fish spurred a flurry of opinions here in California and beyond.

Alejandro Serrano is a reporter on The Chronicle’s metro desk. He previously reported breaking news at The Boston Globe and most recently interned at The Chicago Tribune, where he covered crime and breaking news.